Score skin/ fat (or ask the butcher to do so). Rub pork roast with olive oil. Sprinkle with salt and pepper on all sides.
Roast pork 20-30 minutes until outside is golden and crispy.
Reduce oven to 400°F and roast until thermometer reads 140-145°F (approximately 1 hour to 1 hour 20 minutes).
Rest pork for 15 minutes before slicing.
Pears and Sauce
While pork is resting, in a medium saucepan, melt butter over medium heat. Add pears and onions. Using tongs, carefully flip pears to brown the cut sides, about 5-7 minutes. Carefully remove pears to a plate.
Measure juices from the pork, adding chicken broth to make 1 ½ cups. Add to the saucepan.
To scrape the brown bits from the roasting pan the pork was cooked in, add the vinegar and scrape the bits, then add to the saucepan. Add white wine to saucepan.
Mix together cornstarch and water to make a slurry. Add slurry to the sauce and boil to thicken.
Serve pears and sauce over sliced pork.
Notes
Leftovers can be stored in an airtight container in the fridge for up to 4 days. Reheat in the microwave until heated through and refresh flavors with salt & pepper.